# iteration in CFx

 Register Blogs Members List Search Today's Posts Mark Forums Read

 September 7, 2009, 02:52 iteration in CFx #1 New Member   Hasan Fawad Join Date: Sep 2009 Posts: 1 Rep Power: 0 i am new user of CFX but i have used ANSYS a lot, there is a confusion between iteration of ansys and cfx. in ansys iteration determines how many attempts the solver should make to converge but in CFX one can also apply boundary condition like heat flux for a range of iterations which i cannot comprehend. can someone explain

 September 7, 2009, 07:44 #2 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 10,803 Rep Power: 85 ANSYS and CFX are totally different in their numerical approach so the concept of an "iteration" in each is totally different. Yes, in CFX you can make boundary conditions a function of iteration number but the only time you would do this is to ramp an unstable boundary condition in to make the numerics easier - the fully converged solution should have all boundaries fully active. In ANSYS structural a direct solver will not iterate at all, or an iterative solver will iterate in the linear solver to get a solution to the matrix. Structural non-linearities (eg contact) may introduce further layers of iterations on top of that. In CFX you almost always have two levels of iterations. The lowest layer is the linear solver, which is solving the linear equations in matrix form. CFX uses a multigrid solver to do this. You do not see these iterations in the output file, just the final convergence obtained by default. The higher layer is the "iterations" you see which is where the non-linear nature of the Navier Stokes equations is captured. This is the iterations you see in the output file.

 Thread Tools Display Modes Linear Mode

 Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Smilies are On [IMG] code is On HTML code is OffTrackbacks are On Pingbacks are On Refbacks are On Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post Val Main CFD Forum 3 June 10, 2011 02:20 Javier Larrondo FLUENT 0 October 28, 2007 23:30 Rui CFX 9 May 28, 2007 05:59 Pandu Sattvika CFX 1 December 1, 2001 05:07 chiseung FLUENT 16 October 20, 2001 04:36

All times are GMT -4. The time now is 06:47.